Heart Regeneration by Endogenous Stem Cells and Cardiomyocyte Proliferation: Controversy, Fallacy, and Progress

Area of Science:

• Cardiovascular Biology
• Regenerative Medicine
• Stem Cell Research

Background:

• Ischemic heart disease and myocardial infarction lead to cardiomyocyte loss, adverse remodeling, and heart failure, driving the search for cardiac regeneration strategies.
• Cardiac stem cells (CSCs) have been proposed as a therapeutic source for regenerating damaged myocardium, with some showing clinical promise.
• Recent cell tracing studies have cast doubt on the fundamental biology and myogenic potential of previously identified CSCs.

Purpose of the Study:

• To review the historical development and recent challenges concerning cardiac stem cells (CSCs) in cardiac regeneration.
• To evaluate the emerging role of cardiomyocyte proliferation as a mechanism for myocardial repair.
• To critically assess the methodological strengths and limitations of studies investigating CSCs and cardiomyocyte proliferation.

Main Methods:

• Comprehensive literature review of studies on cardiac stem cells (CSCs) over the past decade.
• Analysis of recent cell tracing studies questioning CSC origin and function.
• Evaluation of methodologies used in research on CSCs and cardiomyocyte proliferation, including cell labeling and lineage tracing techniques.

Main Results:

• Evidence from cell tracing studies raises significant concerns regarding the existence and regenerative capacity of previously identified CSCs.
• The proliferation of pre-existing cardiomyocytes is emerging as a potentially more significant contributor to myocardial repair than CSCs.
• Methodological limitations in past and current studies necessitate improved techniques for accurate assessment of cardiomyocyte generation and regeneration.

Conclusions:

• The field of cardiac regeneration requires a re-evaluation of the role and existence of cardiac stem cells (CSCs).
• Future research should focus on advancing technologies for single-cell labeling and lineage tracing to accurately understand cardiomyocyte developmental potential and fate.
• Embracing technological advancements is crucial for overcoming inaccuracies and advancing our understanding of heart regeneration.